LQ9-LSX are pretty big dimension wise, closer in size to the BBC than the SBC. Weight wise, the LQ9 which has alloy heads is about 100lbs more than the SBF with alloy heads. The 5.0 is narrower, and sits lower than the LSX. Don't forget, if you ever want to change the cam in the LQ9, you have to pull the heads to get the lifters out, the cam comes out of the SBF with the heads on. The LSX is becoming the new belly-button engine and is stuffed in anything that rolls. Do what you want, my 2 cents. B)